Add shaders re-implemented in HLSL

These were written against the shaders at revision eddd724e7.
There have been changes made since then, which will need to be mirrored.

See `data/hlsl/README.md` for the current status of each sample.

data/hlsl/scenerendering/scene.frag

@@ -0,0 +1,34 @@
+// Copyright 2020 Google LLC
+
+Texture2D textureColorMap : register(t0, space1);
+SamplerState samplerColorMap : register(s0, space1);
+
+struct VSOutput
+{
+[[vk::location(0)]] float3 Normal : NORMAL0;
+[[vk::location(1)]] float3 Color : COLOR0;
+[[vk::location(2)]] float2 UV : TEXCOORD0;
+[[vk::location(3)]] float3 ViewVec : TEXCOORD1;
+[[vk::location(4)]] float3 LightVec : TEXCOORD2;
+};
+
+struct Material
+{
+	float4 ambient;
+	float4 diffuse;
+	float4 specular;
+	float opacity;
+};
+[[vk::push_constant]] Material material;
+
+float4 main(VSOutput input) : SV_TARGET
+{
+	float4 color = textureColorMap.Sample(samplerColorMap, input.UV) * float4(input.Color, 1.0);
+	float3 N = normalize(input.Normal);
+	float3 L = normalize(input.LightVec);
+	float3 V = normalize(input.ViewVec);
+	float3 R = reflect(-L, N);
+	float3 diffuse = max(dot(N, L), 0.0) * material.diffuse.rgb;
+	float3 specular = pow(max(dot(R, V), 0.0), 16.0) * material.specular.rgb;
+	return float4((material.ambient.rgb + diffuse) * color.rgb + specular, 1.0-material.opacity);
+}